A diet enriched in a polyunsaturated fatty acid, eicosapentaenoic acid, markedly retards the development of autoimmunity in (NZB x NZW)F1 females. This works even after the onset of disease. Human trials are being designed. Cyclophosphamide is effective treatment in a variety of autoimmune strains unrelated to the cellular basis of illness or the nature (B or T cell) of the proliferating cells. This therapy is effective against the lymphadenopathy of MRL-1pr/1pr mice and the coronary artery disease of BXSB and (NZW x BXSB)F1 mice as well as the renal disease of most examples of murine lupus.